EFFICACY OF THAI TRADITIONAL HERB EXTRACTS AGAINST FISH AND SHRIMP PATHOGENIC BACTERIA

Sixteen species of Thai traditional herbs were selected for this study . They were Andrographis paniculata, Cassia alata, Clinacanthus nutans , Eclipta alba, Momordica charantia, Phyllanthus acidus, P. amarus, P. debilis, P. pulcher, P. reticulatus, P. urinaria, Psidium guajava, Ti nospora cordifolia, T. crispa and white and red strains of Ocimum sanc tum. Using an agar plate dilution method, they were tested for antibac terial activity against the pathogenic bacteria: Aeromonas hydrophila, a Streptococcus species and 10 strains of Vibrio. Eleven of the teste d herbs showed antibacterial activity. Among them, P. guajava and M. c harantia displayed the highest activity against Vibrio harveyi and V. parahaemolyticus. The minimal inhibitory concentration (MIC) of P. gua java against the tested bacteria was found to be 0.625 mg/ml, while th e MIC of M. charantia was 1.25 mg/ml.